I use paint.net to draw the sprites. It is very much possible to use other programs like gimp and such, I just like paint.net, because it's simple and easy to learn. Also it supports transparency and layers unlike normal paint.
For the Djinn sprite i first took the goblin fighter as a canvas, and the djinn (monster) as a colour palette.
goblin, and more like the djinn. I then started making many minor changes, to make it look less like the goblin, and more like a new thing. Then when I were please with how it looked, I started makign the cloud part.
I started by just drawing up swirly clouds with a blackoutline, then I copied the colours from the djinn's cloud chair, and used that as a shading.
And then i took a hand from the goblin fighter, and thief and simply recoloured them, and smoothed them out a little bit. and then added facial hair.
Goblin Fighter +
Djinn (Monster) +
Goblin Thief =
Djinn
For my ratling sprite, I used the halfling thief as canvas, and just painted on top of it
For the ADVENTURER.EXE I took the class-less sprites of races, and made them robot looking.
The witchdoctor I made from scratch.
Edit : I tried to make a djinn with blue gardinet-ed clouds, but I can't quite get it to look a way that I like
Edit 2: I attempted to make a weaker form of spell balance, but I'm affraid
♦Spellbound/Spellcycle♦
♦Using a glyph reduces the mana cost of all other glyphs by 2(stacks twice, however the second stack will only be half as effective (capping the mana cost reduction at 3)). Using glyph with reduced cost resets it's mana cost. (BLUDTOPOWA is not affected by, and cannot trigger spellcycle)
♦base Mana cost of all glyphs is increased by 1